It is known that an organic polymer having at least one reactive silicon group in the molecule undergoes crosslinking by formation of siloxane bonds accompanying a hydrolysis reaction or the like of the reactive silicon group with moisture or the like even at room temperature, and a rubber-like cured article can be obtained.
Among the polymers having a reactive silicon group, organic polymers in which the main chain skeleton is a polyoxyalkylene polymer and/or a (meth)acrylate polymer are disclosed in (Patent Document 1), (Patent Document 2) and the like. Those polymers have already been industrially produced, and are widely used in applications to sealants, adhesives, coatings and the like.
Curable compositions comprising the above described organic polymers having a reactive silicon group are cured by using silanol condensation catalysts, and usually organotin catalysts having a carbon-tin bond such as dibutyltin bis(acetylacetonate) are widely used. However, in recent years, toxicity of organotin compounds is pointed out, and development of non-organotin catalysts are demanded.
Dealcoholization type silicone compositions using organic titanates as a non-organotin catalyst are available on the market, and are widely used in a variety of applications. This technique is disclosed in (Patent Document 3), (Patent Document 4) and the like.
Also examples of adding an organic titanate to organic polymers containing a reactive silicon group are disclosed in (Patent Document 5), (Patent Document 6), (Patent Document 7), (Patent Document 8), (Patent Document 9), (Patent Document 10), (Patent Document 11), (Patent Document 12), (Patent Document 13) and (Patent Document 14).
On the other hand, as disclosed in (Patent Document 15), (Patent Document 16), (Patent Document 17) and the like, in some cases, various organic thixotropy-imparting agents are added to curable compositions comprising an organic polymer having a reactive silicon group for the purpose of improving thixotropy.
Patent Document 1: JP-52-73998A
Patent Document 2: JP-59-74149A
Patent Document 3: JP-39-27643B (U.S. Pat. No. 3,175,993)
Patent Document 4: U.S. Pat. No. 3,334,067
Patent Document 5: JP-58-17154A (JP-3-57943B)
Patent Document 6: JP-62-146959A (JP-5-45635B)
Patent Document 7: JP-5-311063A
Patent Document 8: JP-2001-302929A
Patent Document 9: JP-2001-302930A
Patent Document 10: JP-2001-302931A
Patent Document 11: JP-2001-302934A
Patent Document 12: JP-2001-348528A
Patent Document 13: JP-2002-249672A
Patent Document 14: JP-2003-165916A
Patent Document 15: JP-6-1826A
Patent Document 16: JP-8-143850A
Patent Document 17: JP-2002-322379A